Moon

The moon is Earth's satellite and orbits the Earth at a distance of about 384 thousand km (239 thousand miles). It takes the moon 27 Earth days to rotate on its axis and orbit the earth, which is why we always see the same face of the moon.

Its atmosphere cannot support life, but the moon's influence on life on Earth is undeniable. It's gravitational pull causes the Earth's tides to rise and fall, predictably. There are technically eight phases of the moon one when the moon is dark, three as it's becoming full, a full moon, and three phases as it decreases.

The phases are: new, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent. During eclipses, the moon, Earth and sun are in a straight line casting a shadow on Earth.